Keith said:
First, identify what causes homosexuality.
Then determine if the cause, compared to heterosexuality, is some sort of failure or simply an alternative.
There are plenty of causes, and I'm not sure why the cause would be the issue - rather than the phenomenon we're dealing with, namely homosexuality.
But still, okay, you say one needs to determine whether the cause is "some sort of failure". Do you think there is objective failure?
If so, I would ask: what procedure do we have in order to determine whether something is a failure?
By the way, would you agree then that those who do not know what causes homosexuality (i.e., all of us) should remain undecided as to whether it's a mental illness?
I'm not saying that that is not so. I'm just asking (in order to address the issue of objectivity depending on your reply).
Keith said:
For example, having a left eye that's dominant would probably not be an illness of the right eye.
But we do not know what causes having a left eye that's dominant. So, Do dou think that we do not know whether having a left eye that's dominant is an illness? (maybe not an illness of the right eye, but an illness of the brain). Should we remain undecided?
Similarly, we do not know what causes left-handedness.
But even without knowing whether those are illnesses, it seems you agree that there is objective illness, and there is a fact of the matter as to whether or not they're illnesses, right?
Keith said:
Being blind in the left eye would be an illness.
At least for most of the time humans have been around, the causes of blindness from birth (in one or both eyes) were unknown.
So, given that they did not know the causes, should people have remained undecided as to whether people born blind had an illness?
Or do you think there is an alternative procedure, which doesn't need to take a look at the causes? If so, why can't that procedure be applicable to homosexuality? Moreover, why can't a similar procedure (if there is one in the case of blindness, and which does not look at the causes) be appliable to moral questions?
More to the point: why do you think that there is objective mental illness? Do you see any difference (in terms of procedures to ascertain cases) between mental illness and moral badness, that makes a difference regard to objectivity?